I think it's a great way to summarize and capture any long stretches of time you want to skip as it fits into the way that history books need to be concise and how they often can be vauge due to lack of first hand refrences.
Author how about you add the lords of the night as executioners, torturers and you can also add primarchs who will be similar to the original but they are not
Well like that it can be think that all the soldiers where wizards. To Bad the reality for them is that they were mundane humans , upgrade with Magic and pure training